Highly thermally conductive polypropylene/graphene composites for thermal management

•The unique matrix functionalization strategy was proposed to improve it's polarity.•PP/PDA/G composites with 3D network were fabricated by a simple method.•Through-plane TC of the composite reaches 10.93 W·m−1·K−1.•The obtained composite shows excellent heat dissipation for LED. As an indispensable part of electronic devices, efficient thermal management materials can promote heat dissipation of electronic products quickly, thereby greatly improving their reliability, stability and service life. Here, a simple “in-situ building” approach was developed to fabricate highly thermally conductive polypropylene (PP)/graphene composites with three-dimensional graphene framework. Different from conventional filler modification, a unique matrix functionalization method, inspired by mussel, was carried out to form the interaction (hydrogen bonding and π-π conjugate) between PP and graphene, which greatly reduced interfacial thermal resistance. The obtained composite exhibits a quite high through-plane thermal conductivity (10.93 W·m−1·K−1, almost 55 times higher than that of pure PP), and shows excellent heat dissipation when used as a thermal management material in LED integration. The composite has the potential application in heat dissipation of high power and highly integrated electronic devices.